Novel copolymers and photoresist compositions comprising same

ABSTRACT

The present invention includes polymers and photoresist compositions that comprise the polymers as a resin binder component. Photoresists of the invention include chemically-amplified positive-acting resists that can be effectively imaged at short wavelengths such as sub-200 nm, particularly 193 nm. Polymers of the invention suitably contain 1) photoacid labile groups that preferably contain an alicyclic moiety; 2) a polymerized electron-deficient monomer; 3) a polymerized cyclic olefin moiety. Particularly preferred polymers of the invention are tetrapolymers or pentapolymers, preferably with differing polymerized norbornene units.

[0001] This application claims the benefit of U.S. provisionalapplication No. 60/185,345, filed Feb. 26, 2000, incorporated herein byreference in its entirety.

BACKGROUND OF THE INVENTION

[0002] 1. Field of the Invention

[0003] The present invention relates to new polymers and use of suchpolymers as a resin binder component for photoresist compositions,particularly chemically-amplified positive-acting resists that can beeffectively imaged at short wavelengths such as sub-200 nm, particularly193 nm.

[0004] 2. Background

[0005] Photoresists are photosensitive films used for transfer of imagesto a substrate. A coating layer of a photoresist is formed on asubstrate and the photoresist layer is then exposed through a photomaskto a source of activating radiation. The photomask has areas that areopaque to activating radiation and other areas that are transparent toactivating radiation. Exposure to activating radiation provides aphotoinduced chemical transformation of the photoresist coating tothereby transfer the pattern of the photomask to the photoresist-coatedsubstrate. Following exposure, the photoresist is developed to provide arelief image that permits selective processing of a substrate.

[0006] A photoresist can be either positive-acting or negative-acting.For most negative-acting photoresists, those coating layer portions thatare exposed to activating radiation polymerize or crosslink in areaction between a photoactive compound and polymerizable reagents ofthe photoresist composition. Consequently, the exposed coating portionsare rendered less soluble in a developer solution than unexposedportions. For a positive-acting photoresist, exposed portions arerendered more soluble in a developer solution while areas not exposedremain comparatively less developer soluble. Photoresist compositionsare described in Deforest, Photoresist Materials and Processes, McGrawHill Book Company, New York, ch. 2, 1975 and by Moreau, SemiconductorLithography, Principles, Practices and Materials, Plenum Press, NewYork, ch. 2 and 4.

[0007] More recently, chemically-amplified-type resists have beenincreasingly employed, particularly for formation of sub-micron imagesand other high performance applications. Such photoresists may benegative-acting or positive-acting and generally include manycrosslinking events (in the case of a negative-acting resist) ordeprotection reactions (in the case of a positive-acting resist) perunit of photogenerated acid. In the case of positivechemically-amplified resists, certain cationic photoinitiators have beenused to induce cleavage of certain “blocking” groups pendant from aphotoresist binder, or cleavage of certain groups that comprise aphotoresist binder backbone. See, for example, U.S. Pat. Nos. 5,075,199;4,968,581; 4,883,740; 4,810,613; and 4,491,628, and Canadian PatentApplication 2,001,384. Upon cleavage of the blocking group throughexposure of a coating layer of such a resist, a polar functional groupis formed, e.g., carboxyl or imide, which results in differentsolubility characteristics in exposed and unexposed areas of the resistcoating layer. See also R. D. Allen et al., Proceedings of SPIE,2724:334-343 (1996); and P. Trefonas et al. Proceedings of the 11thInternational Conference on Photopolymers (Soc. Of Plastics Engineers),pp 44-58 (Oct. 6, 1997).

[0008] While currently available photoresists are suitable for manyapplications, current resists also can exhibit significant shortcomings,particularly in high performance applications such as formation ofhighly resolved sub-half micron and sub-quarter micron features.

[0009] Consequently, interest has increased in photoresists that can bephotoimaged with short wavelength radiation, including exposureradiation of about 250 nm or less, or even about 200 nm or less, such aswavelengths of about 248 nm (provided by KrF laser) or 193 nm (providedby an ArF exposure tool). See European Published Application EP915382A2.Use of such short exposure wavelengths can enable formation of smallerfeatures. Accordingly, a photoresist that yields well-resolved imagesupon 248 nm or 193 nm exposure could enable formation of extremely small(e.g. sub-0.25 μm) features that respond to constant industry demandsfor smaller dimension circuit patterns, e.g. to provide greater circuitdensity and enhanced device performance.

[0010] However, many current photoresists are generally designed forimaging at relatively higher wavelengths, such as G-line (436 nm) andI-line (365 nm) are generally unsuitable for imaging at shortwavelengths such as sub-200 nm. Even shorter wavelength resists, such asthose effective at 248 nm exposures, also are generally unsuitable forsub-200 nm exposures, such as 193 nm imaging.

[0011] More specifically, current photoresists can be highly opaque toextremely short exposure wavelengths such as 193 nm, thereby resultingin poorly resolved images.

[0012] It thus would be desirable to have new photoresist compositions,particularly resist compositions that can be imaged at short wavelengthssuch as sub-200 nm exposure wavelengths, particularly 193 nm.

SUMMARY OF THE INVENTION

[0013] We have now found novel polymers and photoresist compositionsthat comprise the polymers as a resin binder component. The photoresistcompositions of the invention can provide highly resolved relief imagesupon exposure to extremely short wavelengths, particularly sub-200 nmwavelengths such as 193 nm.

[0014] In particular, photoresists that contain preferred polymers ofthe invention can exhibit significant resistance to plasma etchants.See, for instance, the results set forth in Example 7, which follows.

[0015] In a first aspect of the invention, polymers are provided thatcontain at least three distinct repeat units as follows:

[0016] 1) a group that include a photoacid-labile moiety, particularly aphotoacid-labile group that contains an alicyclic group, e.g. aphotoacid-labile ester such as a polymerized alkyl acrylate oralkylmethacrylate preferably where the alkyl group is an alicyclic suchas adamantyl, fencyl, and the like;

[0017] 2) a group that contains a polymerized electron-deficient monomerthat is non-photoacid-labile, or at least less reactive (e.g. 2 or 3times less reactive) to photoacid than units 1), such as an ethyleneunsaturated ketone or di-ketone, e.g. an anhydride such as maleicanhydride, itaconic anhydride, citrionic anhydride; amides such asmaleimide; esters, particularly lactones; etc.; and

[0018] 3) a group that includes a polymerized cyclic olefin moiety (i.e.where the olefinic group is polymerized along the polymer backbone toprovide a fused carbon alicyclic group).

[0019] Without being by theory, it is believed the combined use inpolymers of the invention of i) carbon alicyclic groups (provided bypolymerization of a cyclic olefin such as a norbornene); and ii)photoacid-labile groups that contain an alicyclic moiety, can impartsignificantly enhanced resistance to plasma etchants to photoresist thatcontain such polymers. See the comparative results set forth in Example7 below. Such etch resistance can be critical to achieve desired resultsin high performance applications, e.g. forming highly resolved sub-halfmicron or sub-quarter micron resist features.

[0020] Preferred polymers contain at least one additional distinct unit(particularly tetrapolymers or pentapolymers) such as an additional,distinct polymerized cyclic olefin unit. In such tetrapolymers andpentapolymers, suitably at least two distinct polymer units may containphotoacid-acid labile groups. For example, tetrapolymer or pentapolymermay contain a photoacid-labile acrylate and a cyclic olefin, e.g. apolymerized norbornene, that has a photoacid-labile substituent such asa photoacid-labile ester.

[0021] Preferred polymers include those that contain a polymerized firstnorbornene repeat unit, and a polymerized second norbornene repeat unit,where the second unit is distinct from the first unit. For instance, thefirst norbornene repeat unit can be unsubstituted, and the secondnorbornene repeat unit can have one or more non-hydrogen repeat units.Alternatively, the first and second norbornene repeat units each canhave one or more non-hydrogen ring substituents, but where thenon-hydrogen substituent(s) of the first norbornene repeat unit isdifferent than the non-hydrogen substituent(s) of the second norbornenerepeat unit.

[0022] The addition of at least two different norbornene monomersenables desired control of lithographic properties of the polymer,particularly with respect to etch resistance, dissolution contrast,adhesion and resolution. For instance, for enhancing adhesion, a firstnorbornene monomer (e.g. not substituted with any non-hydrogensubstitutents) can be polymerized and a second norbornene monomer thathas one or more alcohol substituents can be polymerized. For enhanceddissolution control, a first norbornene monomer (e.g. not substitutedwith any non-hydrogen substitutents) can be polymerized and a secondnorbornene monomer that has one or more lactone substituents can bepolymerized. For enhanced dissolution contrast, a first norbornenemonomer (e.g. not substituted with any non-hydrogen substituents, orsubstituted with other group such as an alcohol or lactone) can bepolymerized and a second norbornene monomer that has one or morephotoacid-labile substituents can be polymerized.

[0023] Thus, in a preferred aspect of the invention, polymers areprovided that contain at least two distinct polymerized norbornenerepeat units. Preferably such polymers also will containphotoacid-labile groups, either as a substituent of one or both of thetwo distinct norbornene repeat units, or as a polymer repeat unitseparate from the norbornene units. For example, photoacid-labileacrylate units may be present together with the two or more distinctpolymerized norbornene repeat units.

[0024] In a further aspect of the invention, polymers of the inventionare provided that contain at least two distinct units that each havephotoacid labile groups. For instance, a polymer may contain an acrylateunit with a photoacid-labile group, and a polymerized norbornene groupthat has a pendant photoacid-labile group. Alternatively, a polymer ofthe invention may contain at least two distinct photoacid-labileacrylate units.

[0025] In a still further aspect of the invention, polymers of theinvention contain a photoacid labile group that contains a tertiaryester alicyclic hydrocarbon group that has two or more fused or bridgedrings, and in at least certain aspects of the invention, the alicyclichydrocarbon group is preferably other than adamantyl. Preferred tertiaryester groups include optionally substituted fencyl groups, particularlyethyl fencyl; optionally substituted pinanyl; and optionally substitutedtricyclo decanyl, particularly an alkyl-substituted tricyclo decanylsuch as 8-ethyl-8-tricyclodecanyl such as provided by polymerization of8-ethyl-8-tricyclodecanyl acrylate and 8-ethyl-8-tricyclodecanylmethacrylate. Additional alicyclic ester groups also will be suitable,including additional bicyclic, tricyclic and other polycyclic moieties.

[0026] Generally preferred polymers of the invention include those thatcontain at least one repeat unit that comprises a photoacid-labilegroup, which contains an alicyclic hydrocarbon moiety. Polymers of theinvention also may contain multiple, distinct repeat units, e.g. twodistinct repeat units, that each comprise a photoacid-labile group,which contains an alicyclic hydrocarbon moiety.

[0027] The invention also includes polymers that contain one or more ofthe above features. For instance, preferred are terpolymers,tetrapolymers, pentapolymers or other higher order polymers that containat least the above groups 1) through 3), i.e. 1) (photoacid-labilegroup); 2) (polymerized electron-deficient monomer); and 3) (polymerizedcyclic olefin moiety), preferably where at least two distinct units 1)through 3) each has photoacid labile groups, e.g. the cyclic olefin unitmay have a photoacid-labile group. As referred to herein, a cyclicolefin typically refers to a compound that has all carbon ring members(also referred to as a carbon alicyclic). The cyclic olefin will have atleast one endocyclic carbon-carbon double bond and will non-aromatic.The endocyclic double bond can serve to polymerize the cyclic group,providing an alicyclic ring fused to the polymer backbone, i.e. twoadjacent ring carbons of the cyclic group also are part of the polymerbackbone.

[0028] Also preferred are terpolymers, tetrapolymers, pentapolymers orother higher order polymers that contain at least the above groups 1)through 3), and where the polymer contains a photoacid labile group thatcontains a tertiary ester alicyclic hydrocarbon group that has two ormore fused or bridged rings, and suitably is other than adamantyl.

[0029] Polymers of the invention also may contain units in addition tothe above groups. For example, polymers of the invention also maycontain nitrile such as provided by polymerization of methacrylonitrileand acrylonitrile. Additional contrast enhancing groups also may bepresent in polymers of the invention, such as groups provided bypolymermization of methacrylic acid, acrylic acid, and such acidsprotected as photoacid labile esters, e.g. as provided by reaction ofethoxyethyl methacrylate, t-butoxy methacrylate, t-butylmethacrylate andthe like.

[0030] Polymers of the invention are preferably employed in photoresistsimaged at 193 nm, and thus preferably will be substantially free of anyphenyl or other aromatic groups. For example, preferred polymers containless than about 5 mole percent aromatic groups, more preferably lessthan about 1 or 2 mole percent aromatic groups, more preferably lessthan about 0.1, 0.02, 0.04 and 0.08 mole percent aromatic groups andstill more preferably less than about 0.01 mole percent aromatic groups.Particularly preferred polymers are completely free of aromatic groups.Aromatic groups can be highly absorbing of sub-200 nm radiation and thusare undesirable for polymers used in photoresists imaged with such shortwavelength radiation.

[0031] The invention also provides methods for forming relief images,including methods for forming a highly resolved relief image such as apattern of lines where each line has essentially vertical sidewalls anda line width of about 0.40 microns or less, and even a width of about0.25, 0.20 or 0.16 microns or less. The invention further providesarticles of manufacture comprising substrates such as a microelectronicwafer substrate or liquid crystal display or other flat panel displaysubstrate having coated thereon a polymer, photoresist or resist reliefimage of the invention.

[0032] In a still further aspect, the invention includes novel compoundsthat are useful to prepare polymers of the invention. In particular,8-alkyl-8-tricyclodecanyl acrylate and 8-alkyl-8-tricyclodecanylmethacrylate are provided, together with methods of synthesis of thosemonomers.

[0033] Other aspects of the invention are disclosed infra

DETAILED DESCRIPTION OF THE INVENTION

[0034] Polymers of the invention comprise contain one or more repeatunits that comprise a photoacid-labile group. Preferred polymers containa photoacid labile ester group with a tertiary alicyclic hydrocarbonester moiety that is preferably other than adamantyl. Preferred tertiaryalicyclic hydrocarbon ester moieties are polycyclic groups suchethylfencyl group or a tricyclo decanyl moiety. References herein to a“tertiary alicyclic ester group” or other similar term indicate that atertiary alicyclic ring carbon is covalently linked to the ester oxygen,i.e. —C(═O)O—TR where T is a tertiary ring carbon of alicyclic group R.In at least many cases, preferably a tertiary ring carbon of thealicyclic moiety will be covalently linked to the ester oxygen, such asexemplified by the below depicted specifically preferred polymers.However, the tertiary carbon linked to the ester oxygen also can beexocyclic to the alicyclic ring, typically where the alicyclic ring isone of the substituents of the exocyclic tertiary carbon (see forinstance the substituted cyclohexyl group below having a molecularvolume of 161 Å³). Typically, the tertiary carbon linked to the esteroxygen will be substituted by the alicyclic ring itself, and/or one, twoor three alkyl groups having 1 to about 12 carbons, more typically 1 toabout 8 carbons, even more typically 1, 2, 3 or 4 carbons. The alicyclicgroup also suitably will not contain aromatic substitution. Thealicyclic groups may be suitably monocyclic, or polycyclic, particularlybicyclic or tricyclic groups.

[0035] Polymers of the invention also may contain photoacid-labilegroups that do not contain an alicyclic moiety. For example, polymers ofthe invention may contain photoacid-labile ester units, such as aphotoacid-labile alkyl ester. Generally, the carboxyl oxygen (i.e. thecarboxyl oxygen as underlined as follows: —C(═O)O) of thephotoacid-labile ester will be covalently linked to quaternary carbon.References herein to a “quaternary” carbon indicate the carbon atom hasfour non-hydrogen substituents (i.e. CRR¹R²R³ where R, R¹, R¹ and R³ areeach the same or different and each is other than hydrogen). See, forinstance, Morrison and Boyd, Organic Chemistry, particularly at page 85(3^(rd) ed., Allyn and Bacon), for a discussion of the term quaternary.More particularly, preferred non-cyclic photoacid labile groups includet-butyl esters and more highly branched systems where the ester groupcomprises an optionally substituted alkyl moiety having about 5 orpreferably 6 or more carbon atoms, with at least two branched carbonatoms, i.e. at least two secondary, tertiary or quaternary carbon atoms.Suitable alkyl moieties include those that have one, two or moretertiary carbon atoms, and/or one, two or more quaternary carbons.References herein to a “secondary” carbon indicate the carbon atom hastwo non-hydrogen substituents (i.e. CH₂RR¹ where R and R¹ are the sameor different and each is other than hydrogen); references herein to a“tertiary” carbon indicate the carbon atom has three non-hydrogensubstituents (i.e. CHRR¹R² where R, R¹ and R² are the same or differentand each is other than hydrogen). See, again, Morrison and Boyd, OrganicChemistry, particularly at page 85 (3^(rd) ed., Allyn and Bacon), for adiscussion of those terms secondary and tertiary. It also should beunderstood that references herein to “alkyl” are inclusive of linked orbranched carbon chains such as alkylidene, alkylene and the like.

[0036] Some preferred highly branched photoacid-labile esters includethe following:

[0037] Polymers of the invention may contain units in addition to thealkyl esters units described above. For example, polymers may containadditional photoacid-labile groups such as pendant esters such as thoseof the formula —WC(═O)OR⁵, wherein W is a linker such as a chemicalbond, an alkylene particularly C₁₋₃ alkylene, or carbocyclic aryl suchas phenyl, or aryloxy such as phenoxy, and R⁵ is a suitable ester moietysuch as an optionally substituted alkyl (including cycloalkyl) suitablyhaving from 1 to about 20 carbons, more preferably about 4 to about 12carbons, but without a noncyclic or single ring alkyl group having 5 ormore carbons and two or more secondary, tertiary or quaternary carbons;optionally substituted alkenyl (including cycloalkenyl) group suitablyhaving from 2 to about 20 carbons, more preferably about 4 to about 12carbons; optionally substituted alkynyl group suitably having from 2 toabout 20 carbons, more preferably about 4 to about 12 carbons;optionally substituted alkoxy group suitably having from 1 to about 20carbons, more preferably 2 to about 12 carbons; or a heteroalicyclicgroup that contains one or more N, O or S atoms and one or more ringshaving from 4 to about 8 ring members such as tetrahydrofuranyl,thienyl, tetrahydropyranyl, morpholino and the like. Specificallypreferred R⁵ groups include e.g. t-butyl, tetrahydropyran, ethoxyethyl,or an alicyclic group including bridged groups such as such as adamantylincluding 2-methyl-2-adamantyl, norbornyl, isobornyl and the like.Polymers of the invention also may contain aromatic units, such aspolymerized vinylphenol, styrene units and the like. Such aromatic unitsare particularly suitable for polymers used in photoresists imaged at248 nm. However, as discussed above, for even shorter wavelengthimaging, such as 193 nm, preferably a polymer is substantially,essentially or completely free of aromatic units.

[0038] Preferred polymers of the invention include those of thefollowing Formula I:

[0039] wherein R provides a photoacid-labile moiety and is a non-cyclicalkyl or more preferably tertiary alicyclic group such as optionallysubstituted alkyl fenchyl, optionally substituted tricyclo decanyl,optionally substituted pinanyl, or optionally substituted alkyladamantyl;

[0040] R¹ is hydrogen or optionally substituted alkyl such as C₁₋₆alkyl, and preferably R¹ is hydrogen or methyl;

[0041] R² is a non-hydrogen substituent such as C₁₋₈ alkyl; C₁₋₈ alkoxy;a photoacid-labile group such as t-butyl ester and the like; analicyclic group such as cyclohexyl and the like; a lactone; etc.

[0042] Y is a polymerized fused, cyclic olefin unit, preferably forminga five, six, seven or eight membered carbon alicyclic ring with twocarbons of the polymer backbone, such as provided by an optionallysubstituted polymerized norbornene (the curved lines linking Y to thepolymer backbone in Formula I designating the variable ring size);

[0043] Z is an a polymerized electron-deficient monomer which may linkedto a single carbon of the polymer backbone, or may form a ring with twocarbons of the polymer backbone such as a polymerized maleic anhydride(the dashed lines linking Z to the polymer backbone designating that Zmay be linked to one or two carbons of the polymer backbone, and that Zmay be of variable ring size);

[0044] n is an integer of from 0 (where the cyclic olefin group isunsubstituted) to about 6, 7 or 8, and preferably n is 0, 1 or 2;

[0045] a, b and c are each mole percent of the depicted polymer unitsand are each greater than 0. Preferably a is 1 to about 30, 40, 50, 60or 70 mole percent, and b and c are each preferably 10 to 30, 40 or 50mole percent.

[0046] As discussed above, tetrapolymers or pentapolymers are preferredsuch as polymers that contain distinct polymerized cyclic olefin units,in addition to photoacid-labile units and other units, e.g. polymers ofthe following Formula II:

[0047] wherein R, R¹, Y, Z and R², n, a, b, and c are the same asdefined above for Formula I; and

[0048] Y′ is the same as defined for Y in Formula I (but not does haveany non-hydrogen substituents); and b′ is the same as defined for b inFormula I.

[0049] Particularly preferred polymers of the invention include astructure of the following Formula III:

[0050] wherein R¹, R², R³ and R⁴ are each independently hydrogen or anon-hydrogen substituent, and R¹ and R² together are different than R³and R⁴ together (i.e. so that polymerized norbornene unit 1 is differentthan polymerized norbornene unit 2), and R¹ and R² may be takentogether, and R³ and R⁴ may be taken together to form a fused ring, e.g.a ring having 5, 6, 7 or 8 carbon ring members;

[0051] R⁵ is a moiety that provides a photoacid-labile group, such as atertiary alicyclic group as discussed above, or a branched non-cyclicoptionally substituted alkyl group, wherein the ester carboxyl group isdirectly bonded to a quaternary carbon atom;

[0052] R⁶ is hydrogen or alkyl, preferably C₁₋₆ alkyl particularlymethyl;

[0053] a, b, c and d are each mole fractions of the respective polymerunits and are each greater than zero.

[0054] In Formula III, preferably a is from 5 to 40 mole percent, morepreferably 5 to 20 mole percent; preferably b is from 5 to 40 molepercent, more preferably 5 to 20 mole percent; preferably c is from 10to 50 mole percent, more preferably 20 to 40 mole percent; andpreferably d is from 5 to 70 mole percent, more preferably 10 to 50 molepercent.

[0055] In Formula III, preferably the sum of a, b, c and d is at leastabout 70 mole percent (i.e. at least 70 mole percent of the totalpolymer consists of the above depicted units 1, 2, 3 and 4), morepreferably the sum of a, b, c and d is at least about 80, 90 or 95 molepercent of total polymer units, or the sum of a, b, c and d is about 100mole percent of total polymer units.

[0056] Preferred alicyclic moieties (e.g. R⁵ in Formula III above) ofphotoacid labile ester groups of polymers of the invention have ratherlarge volume. It has been found that such bulky alicyclic groups canprovide enhanced resolution when used in copolymers of the invention.

[0057] More particularly, preferred alicyclic groups of photoacid labileester groups will have a molecular volume of at least about 125 or about130 Å³, more preferably a molecular volume of at least about 135, 140,150, 155, 160, 165, 170, 175, 180, 185, 190, 195, or 200 Å³. Alicyclicgroups larger than about 220 or 250 Å³ may be less preferred, in atleast some applications. References herein to molecular volumesdesignate volumetric size as determined by standard computer modeling,which provides optimized chemical bond lengths and angles. A preferredcomputer program for determining molecular volume as referred to hereinis Alchemy 2000, available from Tripos. For a further discussion ofcomputer-based determination of molecular size, see T Omote et al,Polymers for Advanced Technologies, volume 4, pp. 277-287.

[0058] Some specifically preferred alicyclic groups of acid labileesters of the invention are shown immediately below together with theester oxygen linkage, and with volumetric size values (Å³) listed to theright of the alicyclic group.

[0059] Additional preferred alicyclic moieties of ester groups ofpolymers of the invention include the following, where the wavy lineindicates the covalent linkage to the carboxyl oxygen of the estergroup:

[0060] wherein in the above depicted structures, R is suitablyoptionally substituted alkyl, preferably optionally substituted C₁₋₈alkyl, more preferably optionally substituted C₁₋₆ alkyl such a methyl,ethyl, propyl and the like.

[0061] Particularly preferred polymers of the invention include thefollowing:

[0062] In those above polymers structures, “LG” desingates aphotoacid-labile leaving group and is suitably the same as defined forsubstituent R⁵ in Formula III above and is preferably methyladamantyl,8-ethyl-8-tricyclodecanyl and the like. R¹ in the above polymerstructures is suitably C₁₋₁₂ alkyl, such as methyl, ethyl, propyl andthe like. The group n is suitably an integer of 1, 2, 3, or 4, andpreferably is 1 or 2. R² in the above polymer structures is suitablyhydrogen or C₁₋₈ alkyl, preferably methyl.

[0063] Specifically preferred polymers of the invention include thefollowing, with specifically preferred molar ratios of the respectivepolymer units shown to the right of the depicted polymer:

[0064] Polymers of the invention can be prepared by a variety ofmethods. One suitable method is an addition reaction which may includefree radical polymerization, e.g., by reaction of selected monomers toprovide the various units as discussed above in the presence of aradical initiator under an inert atmosphere (e.g., N₂ or argon) and atelevated temperatures such as about 70° C. or greater, although reactiontemperatures may vary depending on the reactivity of the particularreagents employed and the boiling point of the reaction solvent (if asolvent is employed). Suitable reaction solvents include e.g.tetrahydrofuran, ethyl lactate and the like. Suitable reactiontemperatures for any particular system can be readily determinedempirically by those skilled in the art based on the present disclosure.A variety of free radical initiators may be employed. For example, azocompounds may be employed such as azo-bis-2,4-dimethylpentanenitrile.Peroxides, peresters, peracids and persulfates also could be employed.

[0065] As discussed above, the invention also include novel compoundsthat are useful to prepare polymers of the invention, particularly8-alkyl-8-tricyclodecanyl acrylate, preferably8-(C₁₋₁₆alkyl)-8-tricyclodecanyl acrylate such as8-propyl-8-tricyclodecanyl acrylate, 8-ethyl-8-tricyclodecanyl acrylate,and 8-methyl-8-tricyclodecanyl acrylate; 8-alkyl-8-tricyclodecanylmethacrylate, preferably 8-(C₁₋₁₆alkyl)-8-tricyclodecanyl methacrylatesuch as 8-propyl-8-tricyclodecanyl methacrylate,8-ethyl-8-tricyclodecanyl acrylate, and 8-methyl-8-tricyclodecanylmethacrylate, such as compounds of the following structures:

[0066] Those above tricyclodecanyl compounds can be synthesized byreaction of an alkyl Grignard reagent such as ethylmagnesium chloride,with a tricyclodecane compound and an acroyl or methacroyl compound,preferably such as methacryolyl chloride (to provide a tricyclodecanylmethacrylate) or acryolyl chloride (to provide a tricyclodecanylacrylate). The reaction is preferably conducted in a suitable non-proticsolvent such as tetrahydrofuran. Preferably the Grignard reagent andtricyclodecane compound are admixed solvent at reduced temperature withslow addition (e.g. 0.25, 0.5, 1.0 hours or more hours) of the acroyl ormethacroyl compound. The reaction mixture can be allowed to warm to roomtemperature with stirring, e.g. overnight. See Example 1 which followsfor exemplary preferred conditions.

[0067] Other monomers that can be reacted to provide a polymer of theinvention can be identified by those skilled in the art. For example, toprovide units of Formula I, suitable monomers include e.g. methacrylateor acrylate that contains the appropriate R group substitution on thecarboxy oxygen of the ester group. Itaconic anhydride is anotherpreferred reagent, preferably purified such as by extraction withchloroform. Vinyl lactones are also preferred reagents, such asalpha-butyrolactone.

[0068] As discussed, various moieties may be optionally substituted,including groups of Formulae I, II and III. A “substituted” substituentmay be substituted at one or more available positions, typically 1, 2,or 3 positions by one or more suitable groups such as e.g. halogen(particularly F, Cl or Br); C₁₋₈ alkyl; C₁₋₈ alkoxy; C₂₋₈ alkenyl; C₂₋₈alkynyl; hydroxyl; alkanoyl such as a C₁₋₆ alkanoyl e.g. acyl and thelike; etc

[0069] Preferably a polymer of the invention will have a weight averagemolecular weight (Mw) of about 800 or 1,000 to about 100,000, morepreferably about 2,000 to about 30,000, still more preferably from about2,000 to 15,000 or 20,000, with a molecular weight distribution (Mw/Mn)of about 3 or less, more preferably a molecular weight distribution ofabout 2 or less. Molecular weights (either Mw or Mn) of the polymers ofthe invention are suitably determined by gel permeation chromatography.

[0070] Polymers of the invention used in photoresist formulations shouldcontain a sufficient amount of photogenerated acid labile ester groupsto enable formation of resist relief images as desired. For instance,suitable amount of such acid labile ester groups will be at least 1 molepercent of total units of the polymer, more preferably about 2 to 40,50, 60 or 70 mole percent, still more typically about 3 to 30, 40, 50,60 or 70 mole percent of total polymer units. See the examples whichfollow for exemplary preferred polymers.

[0071] As discussed above, the polymers of the invention are highlyuseful as a resin binder component in photoresist compositions,particularly chemically-amplified positive resists. Photoresists of theinvention in general comprise a photoactive component and a resin bindercomponent that comprises a polymer as described above.

[0072] The resin binder component should be used in an amount sufficientto render a coating layer of the resist developable with an aqueousalkaline developer.

[0073] The resist compositions of the invention also comprise aphotoacid generator (i.e. “PAG”) that is suitably employed in an amountsufficient to generate a latent image in a coating layer of the resistupon exposure to activating radiation. Preferred PAGs for imaging at 193nm and 248 nm imaging include imidosulfonates such as compounds of thefollowing formula:

[0074] wherein R is camphor, adamantane, alkyl (e.g. C₁₋₁₂alkyl) andperfluoroalkyl such as perfluoro(C₁₋₁₂alkyl), particularlyperfluorooctanesulfonate, perfluorononanesulfonate and the like. Aspecifically preferred PAG isN-[(perfluorooctanesulfonyl)oxy]-5-norbornene-2,3-dicarboximide.

[0075] Sulfonate compounds are also suitable PAGs, particularlysulfonate salts. Two suitable agents for 193 nm and 248 nm imaging arethe following PAGS 1 and 2:

[0076] Such sulfonate compounds can be prepared as disclosed in EuropeanPatent Application 96118111.2 (publication number 0783136), whichdetails the synthesis of above PAG 1.

[0077] Also suitable are the above two iodonium compounds complexed withanions other than the above-depicted camphorsulfonate groups. Inparticular, preferred anions include those of the formula RSO₃₋ where Ris adamantane, alkyl (e.g. C₁₋₁₂ alkyl) and perfluoroalkyl such asperfluoro (C₁₋₁₂alkyl), particularly perfluorooctanesulfonate,perfluorobutanesulfonate and the like.

[0078] Other known PAGS also may be employed in the resists of theinvention. Particularly for 193 nm imaging, generally preferred are PAGSthat do not contain aromatic groups, such as the above-mentionedimidosulfonates, in order to provide enhanced transparency.

[0079] A preferred optional additive of resists of the invention is anadded base, particularly tetrabutylammonium hydroxide (TBAH), ortetrabutylammonium lactate, which can enhance resolution of a developedresist relief image. For resists imaged at 193 nm, a preferred addedbase is a hindered amine such as diazabicyclo undecene ordiazabicyclononene. The added base is suitably used in relatively smallamounts, e.g. about 0.03 to 5 percent by weight relative to the totalsolids.

[0080] Photoresists of the invention also may contain other optionalmaterials. For example, other optional additives include anti-striationagents, plasticizers, speed enhancers, etc. Such optional additivestypically will be present in minor concentrations in a photoresistcomposition except for fillers and dyes which may be present inrelatively large concentrations, e.g., in amounts of from about 5 to 30percent by weight of the total weight of a resist's dry components.

[0081] The resists of the invention can be readily prepared by thoseskilled in the art. For example, a photoresist composition of theinvention can be prepared by dissolving the components of thephotoresist in a suitable solvent such as, for example, ethyl lactate,ethylene glycol monomethyl ether, ethylene glycol monomethyl etheracetate, propylene glycol monomethyl ether; propylene glycol monomethylether acetate and 3-ethoxyethyl propionate. Typically, the solidscontent of the composition varies between about 5 and 35 percent byweight of the total weight of the photoresist composition. The resinbinder and photoactive components should be present in amountssufficient to provide a film coating layer and formation of good qualitylatent and relief images. See the examples which follow for exemplarypreferred amounts of resist components.

[0082] The compositions of the invention are used in accordance withgenerally known procedures. The liquid coating compositions of theinvention are applied to a substrate such as by spinning, dipping,roller coating or other conventional coating technique. When spincoating, the solids content of the coating solution can be adjusted toprovide a desired film thickness based upon the specific spinningequipment utilized, the viscosity of the solution, the speed of thespinner and the amount of time allowed for spinning.

[0083] The resist compositions of the invention are suitably applied tosubstrates conventionally used in processes involving coating withphotoresists. For example, the composition may be applied over siliconwafers or silicon wafers coated with silicon dioxide for the productionof microprocessors and other integrated circuit components.Aluminum-aluminum oxide, gallium arsenide, ceramic, quartz, copper,glass substrates and the like are also suitably employed.

[0084] Following coating of the photoresist onto a surface, it is driedby heating to remove the solvent until preferably the photoresistcoating is tack free. Thereafter, it is imaged through a mask inconventional manner. The exposure is sufficient to effectively activatethe photoactive component of the photoresist system to produce apatterned image in the resist coating layer and, more specifically, theexposure energy typically ranges from about 1 to 100 mJ/cm², dependentupon the exposure tool and the components of the photoresistcomposition.

[0085] As discussed above, coating layers of the resist compositions ofthe invention are preferably photoactivated by a short exposurewavelength, particularly a sub-300 and sub-200 nm exposure wavelength.As discussed above, 193 nm is a particularly preferred exposurewavelength. 157 nm is another preferred exposure wavelength for resistsof the invention. However, the resist compositions of the invention alsomay be suitably imaged at higher wavelengths. For example, a resin ofthe invention can be formulated with an appropriate PAG and a sensitizerif needed and imaged at higher wavelengths such as about 248 nm or 365nm.

[0086] Following exposure, the film layer of the composition ispreferably baked at temperatures ranging from about 70° C. to about 160°C. Thereafter, the film is developed. The exposed resist film isrendered positive working by employing a polar developer, preferably anaqueous based developer such as quaternary ammonium hydroxide solutionssuch as a tetra-alkyl ammonium hydroxide solution; various aminesolutions preferably a 0.26 N tetramethylammonium hydroxide, such asethyl amine, n-propyl amine, diethyl amine, di-n-propyl amine, triethylamine, or methyldiethyl amine; alcohol amines such as diethanol amine ortriethanol amine; cyclic amines such as pyrrole, pyridine, etc. Ingeneral, development is in accordance with procedures recognized in theart.

[0087] Following development of the photoresist coating over thesubstrate, the developed substrate may be selectively processed on thoseareas bared of resist, for example by chemically etching or platingsubstrate areas bared of resist in accordance with procedures known inthe art. For the manufacture of microelectronic substrates, e.g., themanufacture of silicon dioxide wafers, suitable etchants include a gasetchant, e.g. a halogen plasma etchant such as a chlorine orfluorine-based etchant such a Cl₂ or CF₄/CHF₃ etchant applied as aplasma stream. After such processing, resist may be removed from theprocessed substrate using known stripping procedures.

[0088] All documents mentioned herein are incorporated herein byreference. The following non-limiting examples are illustrative of theinvention.

EXAMPLES 1-4 Monomer Syntheses Example 1 EtTCD Methacrylate MonomerSynthesis

[0089] The monomer of 8-ethyl-8-tricyclodecanyl methacrylate (EtTCDmethacrylate) was prepared as follows using the materials and amountthereof as specified in the following Table. Material Amt (g) Amt (ml)Moles Source TCD 150.22 1.00 TCI Ethylmagnesiumchloride(25%) 390.85˜379.5 ˜1.10 ACROS Methacryloyl chloride 120.22 ˜112.4 1.15 AldrichTetrahydrofuran 480 540 Aldrich

[0090] All reaction glassware was dried in the oven overnight at 100° C.The glassware was set up and cooled under a stream of nitrogen. Thereaction was carried out under a blanket of nitrogen.

[0091] To a 2L 3N-RB flask fitted with a gas inlet, thermometer,overhead stirrer and a rubber septum was added 400 g of ethylmagnesiumchloride, 25 wt % solution in tetrahydrofuran (clear, amber solution)via a double tipped needle using nitrogen pressure. The mixture wascooled to −25 to −30° C. using a dry ice/isopropanol bath. While theethylmagnesium chloride solution was cooling the 153.6 g of TCD(tricyclodecane) was dissolved in 480 g of tetrahydrofuran. To a 1L3N-RB flask equipped with a gas inlet, glass stopper and a rubber septumwas added the 153.6 g of TCD. The anhydrous, inhibitor freetetrahydrofuran was transferred to the 1L flask via a double tippedneedle using nitrogen pressure. When the ethylmagesium chloride was at−25 to −30° C., the TCD/THF solution was transferred over a 2 hr periodto the 2L 3N-RB flask containing the ethylmagnesium chloride via adouble tipped needle using nitrogen pressure. The cooling bath wasremoved and the reaction mixture was stirred for 2 hr. After stirringfor 2 hr the mixture was again cooled to −25 to −30° C. using a dryice/isopropanol bath. The methacryloyl chloride (120.22 g) was thenadded dropwise over a 1 hour period using a 125 ml pressure equalizingdropping funnel. The reaction was allowed to come to room temperaturewith overnight stirring. A white precipitate developed from the clearamber colored reaction solution. Water (DI) was added until all of thesalts had dissolved (˜500 ml) and two distinct layer were seen. Thelayers were separated and the organic (upper) layer was washed with2×400 ml DI water then dried over magnesium sulfate. The THF was removedleaving 258 g of an orange oil. The orange oil was dissolved in 400 g ofhexane then passed through a 400 g silica gel plug which had beenpre-conditioned with hexane. The silica was washed with hexane until allof the product was removed (spot filtrate on a TLC plate and illuminateunder short UV). The hexane was removed leaving 202.8 g of an clear,colorless oil. Theoretical yield: 248.4 g; yield: 81.6%

Example 2 Synthesis of Norbornene Valerolactone

[0092] A solution of valerolactone (50.1 g) in 150 mL of anhydrous THFwas placed in a three-neck-boftomed flask at −78° C. (Dry Ice/acetone).To it, solution of LDA (250 ML, 0.2 M) in 250 mL anhydrous THF was addeddropwise. The reaction mixture was stirred at this temperature for 4hours. Then, the thermal cracking of paraformaldehyde (36.94 g, excess)was bubbled into the reaction mixture. After the paraformaldehyde wasall cracked, the reaction mixture was stirred at the same bath andstirred for overnight. Then, the solvent was removed by rotary pump andthe residue was added 500 mL CH₂Cl₂ and washed with NaHCO₃ (aq, sat.)and water several times (3×500 mL). The combination organic solvent wasdried over MgSO₄ and the solvent was removed by rotary pump. The desiredproduct was distilled under vacuum (135-140° C./8 mmHg)

[0093] The methylene-valerolactone was dissolved in dichloromethane andfreshly cracked cyclopentadiene was added. The reaction mixture wasstirred at room temperature for 3 hours, then heated to 40° C., and heldat 40° C. overnight. The reaction mixture was then slowly cooled to roomtemperature. The methylene chloride was removed under reduced pressure,leaving an oil. The crude oil was then distilled under reduced pressureto afford pure product.

Example 3 Synthesis of 8-methyltricyclodecanyl Methacrylate

[0094]

[0095] A solution of 125 ml of 1.4 M methyl lithium (in ethyl ether) in100 ml of hexane was decanted into a three neck round-bottom flask at anice-water bath. To it, a solution of 24.00 g oftricyclo[5.2.1.0]decan-8-one in hexane was added dropwise. Afteraddition, the reaction mixture was stirred for 4 hours at 0° C. Then, asolution of 16 ml of methacroyl chloride in 100 ml of hexane was addeddropwise at 0° C. After addition, the reaction mixture was stirred atthe same bath for overnight (16 hours). After filtering the white salts,the organic layer was washed with water three times (3×300 ml). Then,the washed organic layer was dried over anhydrous MgSO₄. The organicsolvent was removed by a rotary pump to give the crude title monomer(23.5 g). The monomer was purified by a flash column chromatography(purity >98%, silica gel with hexane). ¹H NMR: 6.05 (1H), 5.50 (1H),1.95 (3H), 1.65 (3H), 2.25-0.85 (14H).

Example 4 Synthesis of Pinanyl Methacrylate

[0096]

[0097] Materials used: Amount Charged Moles Source cis-Pinan-2-ol 15.43g 0.10 Fluka Et₃N 12.14 g 0.12 Aldrich, distilled before useMethacryloyl 13.07 g 0.125 Aldrich, distilled before chloride use CH₂Cl₂230 mL Aldrich, dried and distilled

[0098] Procedure:

[0099] All reaction glassware and needles were dried and flushed withdry N₂ before use and the reaction was carried out under nitrogenatmosphere.

[0100] 1) Into a 500 mL 3-neck round-bottom-flask equipped with anaddition funnel and a magnetic stirrer were added 15.43 g ofcis-pinan-2-ol and 200 mL of dry CH₂Cl₂ (Stirred over CaH₂ overnight,then distilled and stored over activated molecular sieves). Theresulting colorless solution was cooled with an ice-water bath.

[0101] 2) Triethylamine (12.14 g) was added through the addition funnelto the cooled CH₂Cl₂ solution over 10 min. After added, the resultingsolution was kept in a dry-ice/acetone bath (−67° C.).

[0102] 3) A CH₂Cl₂ (30 mL) solution of methacryloyl chloride (13.07 g)was added dropwisely over 20 min. The resulting orangish suspension wasallowed to warm to room temperature and stirred for 2 h.

[0103] 4) The chloride salts were filtered off. The filtrate was washedwith saturated Na₂CO₃ solution (2×200 mL), then DI water (3×200 mL), anddried over anhydrous MgSO_(4.)

[0104] 5) The slightly yellow CH₂Cl₂ solution was concentrated on arotary evaporator (bath temperature kept below 35°) to yield a clearslightly yellow liquid product. Yield=79%. The product was judged pureby NMR.

EXAMPLE 5 Polymer Synthesis

[0105]

[0106] Norbornene pantolactone carboxylate/Norborneneethyltricyclodecane carboxylate/Maleic Anhydride/Ethyl tricyclodecanemethacrylate (molar ratio of respective units: 12.5:32.5:45:10)

[0107] Into a 100 ml Round bottom flask the following was weighted out:Ethyl tricyclodecane methacrylate 2.53 grams (0.010 moles) Norbornenepantolactone carboxylate 3.16 grams (0.013 moles) Maleic Anhydride 8.17grams (0.045 moles) Norbornene ethyltricyclodecane carboxylate 9.86grams (0.033 moles) V601 0.70 grams (0.003 moles) 20 grams THF

[0108] A magnetic stir bar was added to the flask and the solution wasstirred for ˜15 minutes to dissolve the contents of the flask. Once insolution the flask was placed in a hot oil bath, preheated to 80° C. Acondenser and N₂ line was attached on top and the reaction was allowedto stir for 24 hours. After 24 hours the heat was removed and the flaskwas allowed to cool to room temperature. After cooling to roomtemperature the contents of the flask was precipitated into 1.5 L (of50/50 hexanes/IPA w/w). The precipitated solution was stirred for 1.5hours and then the polymer was isolated, via a glass fretted funnel.Washed with 200 grams hexanes. Then the polymer was dried for 4 hours inthe hood and then overnight in a vacuum oven, at room temperature. Thisreaction yielded 10 grams/20 grams of polymer, giving a 50% yield.

EXAMPLE 6 Polymer Synthesis

[0109] A mixture of 2-methyladamantanyl methacrylate (15.00 g, 0.064mol), maleic anhydride (4.71 g, 0.048 mol), norbornene (3.01 g, 0.032mole), norbornyl-cyclopentanol (3.07 g, 0.016 mol), and V601 (1.11 g, 3%mole of total monomers) in 25.79 mL (1/1=monomer/solvent) of inhibitorfree tetrahydrofuran was placed in a round-bottomed flask. Afterstirring for 5 minutes, the flask was put into a pre-heated (70° C.) oilbath. The reaction mixture was stirred at this temperature for 24 hours.After cooling, 25.79 g of THF was added to this flask. The polymer wasisolated by precipitation into 1.5 L of hexane/IPA (1/1, % wt.). Thesuspension mixture was stirred for 120 minutes. Then, the polymer wasfiltered off and washed the polymer by additional 200 mL of hexane. Thepolymer was dried in a vacuum oven at 40° C. for overnight (about 16hours). Yield =80%.

EXAMPLE 7 Etch Resistance of Polymers of the Invention

[0110] Oxide etch rates of polymers of the invention were examined. Thefollowing preferred-tetrapolymer 1 (with molar ratios of tetrapolymerunits shown to the right of the tetrapolymer structure) of the inventionwas tested for oxide etch rate:

[0111] That polymer 1 approximately the same resistance to oxide plasmaetch as that of the following phenolic copolymer (with molar ratios ofcopolymer units shown to the right of the copolymer structure):

[0112] Polymer 1 also exhibited approximately 30% greater resistance tooxide etch relative to the following copolymer (with molar ratios ofpolymer units shown to the right of the polymer structure):

EXAMPLES 8-9 Photoresist Preparation and Lithographic Processing EXAMPLE8

[0113] A photoresist of the invention is prepared by mixing thefollowing components with amount expressed as weight percents based ontotal weight of the resist composition: Resist components Amount (wt. %)Resin binder 15 Photoacid generator 4 Ethyl lactate 81

[0114] The resin binder is the polymer of Example 5 above. The photoacidgenerator is di-(4-t-butylphenyl) iodonium (+/−)-10-camphor sulfonate(PAG 1 above). Those resin and PAG components are admixed in the ethyllactate solvent.

[0115] The formulated resist composition is spin coated onto HMDS vaporprimed 4 inch silicon wafers and softbaked via a vacuum hotplate at 90°C. for 60 seconds. The resist coating layer is exposed through aphotomask at 193 nm, and then the exposed coating layers arepost-exposure baked (PEB) at about 110° C. The coated wafers are thentreated with 0.26 N aqueous tetramethylammonium hydroxide solution todevelop the imaged resist layer and provide a relief image.

EXAMPLE 8

[0116] A further photoresist of the invention is prepared by mixing thefollowing components with amount expressed as weight percents based ontotal weight of the resist composition: Resist components Amount (wt. %)Resin binder 28.2  Photoacid generator  0.52 Base additive  0.03Surfactant  0.03 Solvent to provide 16 wt. % solids

[0117] The resin binder is the polymer of Example 5 above. The photoacidgenerator is triphenylsulfonium triflate. The basic additive istriisopropanol amine. The surfactant is Silwet (Dow Chemical). Thoseresist components were formulated at 16 wt. % solids in a solvent of2-heptatone.

[0118] The formulated resist composition is spin coated onto HMDS vaporprimed 4 inch silicon wafers and softbaked via a vacuum hotplate at 130°C. for 60 seconds. The resist coating layer is exposed through aphotomask at 193 nm, and then the exposed coating layers arepost-exposure baked (PEB) at about 130° C. The coated wafers are thentreated with 0.26 N aqueous tetramethylammonium hydroxide solution todevelop the imaged resist layer and provide a relief image.

[0119] The foregoing description of the invention is merely illustrativethereof, and it is understood that variations and modification can bemade without departing from the spirit or scope of the invention as setforth in the following claims.

What is claimed is:
 1. A photoresist composition comprising aphotoactive component and a resin binder comprising a polymer thatcomprises repeat units of: 1) a group that comprises a photoacid-labilemoiety, the photoacid-labile moiety comprising an alicyclic group; 2) agroup that contains a polymerized monomer comprising ethyleneunsaturated carbonyl or di-carbonyl; and 3) a group that comprises apolymerized cyclic olefin moiety.
 2. The photoresist of claim 1 whereinthe polymer is a tetrapolymer.
 3. The photoresist of claim 1 or 2wherein the polymer comprises polymerized norbornene units.
 4. Thephotoresist of any one of claims 1 through 3 wherein the polymercomprises a first polymerized norbornene repeat unit, and a secondpolymerized norbornene repeat unit, the first and second norborneneunits being different.
 5. The photoresist of claim 4 wherein the firstnorbornene repeat unit does not contain any non-hydrogen ringsubstituents, and the second norbornene repeat unit contains one or morenon-hydrogen ring substituents.
 6. The photoresist of any one of claims1 through 5 wherein the photoacid labile group is an ester group.
 7. Thephotoresist of claim 6 wherein the ester group comprises a tertiaryalicyclic group.
 8. The photoresist of claim 7 wherein the alicyclicmoiety is a bicyclic group.
 9. The photoresist of claim 7 wherein thealicyclic moiety is a tricyclic group.
 10. The photoresist of claim 7wherein the alicyclic moiety is a monocyclic group.
 11. The photoresistof claim 7 wherein the alicyclic group has a molecular volume of atleast about 125 Å³.
 12. The photoresist of claim 7 wherein the alicyclicgroup is optionally substituted fencyl; optionally pinanyl; optionallysubstituted tricyclo decanyl; or optionally substituted adamantyl. 13.The photoresist of claim 7 wherein the alicyclic moiety is provided byreaction of 2-methyladamantyl methacrylate, 2-methyladamantyl acrylate,ethylfenchol methacrylate, ethylfenchol acrylate,8-methyltricyclodecanyl methacrylate, or 8-methyltricyclodecanylacrylate.
 14. The photoresist of claim 6 wherein the ester groupcomprises an optionally substituted non-cyclic alkyl group.
 15. Thephotoresist of claim 14 wherein a quaternary carbon is directly linkedto the ester carboxyl oxygen.
 16. The photoresist of claim 1 wherein thepolymer further comprises one or more units selected from the groupconsisting of an acid; nitrile; an anhydride; a lactone; or a photoacidlabile group that contains a leaving group that has other than analicyclic moiety.
 15. The photoresist of claim 1 wherein the polymercomprises units of the following Formula I:

wherein R is a non-cyclic alkyl or tertiary alicyclic alkyl group; R¹ ishydrogen or optionally substituted alkyl; R² is a non-hydrogensubstituent; Y is a polymerized cyclic olefin unit; Z is an apolymerized electron-deficient monomer; n is an integer of from 0 toabout 8; a, b and c are each mole percent of the depicted polymer unitsand are each greater than
 0. 16. The photoresist of claim 1 wherein thepolymer comprises units of the following Formula II:

wherein R is a non-cyclic alkyl or tertiary alicyclic alkyl group; R¹ ishydrogen or optionally substituted alkyl; R² is a non-hydrogensubstituent; Y and Y′ are the same or different and each are apolymerized cyclic olefin unit; Z is an a polymerized electron-deficientmonomer; n is an integer of from 0 to about 8; a, b, b′ and c are eachmole percent of the depicted polymer units and are each greater than 0.17. The photoresist of claim 1 wherein the polymer comprises units ofthe following Formula III:

R¹, R², R³ and R⁴ are each independently hydrogen or a non-hydrogensubstituent, and R¹ and R² together are different than R³ and R⁴together, and R¹ and R² may be taken together, and R³ and R⁴ may betaken together to form a fused ring; R⁵ is a moiety that provides aphotoacid-labile group; R⁶ is hydrogen or alkyl; a, b, c and d are eachmole fractions of the respective polymer units and are each greater thanzero.
 18. A photoresist composition comprising a photoactive componentand a resin binder comprising a polymer that comprises, repeat units ofat least two distinct norbornene repeat units.
 19. The photoresistcomposition of claim 18 wherein the polymer comprises photoacid-labilegroups.
 20. The photoresist of claim 19 wherein the one or both of thedistinct norbornene units comprises a photoacid-labile moiety.
 21. Thephotoresist of claim 18 or 19 wherein the polymer comprises aphotoacid-labile repeat unit separate from a norbornene unit.
 22. Thephotoresist of claim 21 wherein the polymer comprises an acrylate unithaving a photoacid-labile moiety.
 23. The photoresist of any one ofclaims 18 through 22 wherein the polymer is a tetrapolymer or apentapolymer.
 24. The photoresist of any one of claims 1 through 23wherein the polymer is completely free of aromatic groups.
 25. A methodof forming a positive photoresist relief image, comprising: (a) applyinga coating layer of a photoresist of any one of claims 1 through 24 on asubstrate; and (b) exposing and developing the photoresist layer toyield a relief image.
 26. The method of claim 25 wherein the photoresistlayer is exposed with radiation having a wavelength of less than about200 nm.
 27. The method of claim 25 wherein the photoresist layer isexposed with radiation having a wavelength of about 193 nm.
 28. Anarticle of manufacture comprising a microelectronic wafer substrate orflat panel display substrate having coated thereon a layer of thephotoresist composition of any one of claims 1 through
 24. 29. A polymerthat comprises repeat units of that comprises repeat units of: 1) agroup that comprises a photoacid-labile moiety, the photoacid-labilemoiety comprising an alicyclic group; 2) a group that contains apolymerized monomer comprising ethylene unsaturated carbonyl ordi-carbonyl; and 3) a group that comprises a polymerized cyclic olefinmoiety.
 30. The polymer of claim 29 wherein the polymer is atetrapolymer of pentapolymer.
 31. The polymer of claim 29 or 30 whereinthe polymer comprises polymerized norbornene units.
 32. The polymer ofclaim 29, 30 or 31 wherein the polymer comprises a first polymerizednorbornene repeat unit, and a second polymerized norbornene repeat unit,the first and second norbornene units being different.
 33. The polymerof claim 29 wherein the polymer comprises units of the followingformula:

R¹, R², R³ and R⁴ are each independently hydrogen or a non-hydrogensubstituent, and R¹ and R² together are different than R³ and R⁴together, and R¹ and R² may be taken together, and R³ and R⁴ may betaken together to form a fused ring; R⁵ is a moiety that provides aphotoacid-labile group; R⁶ is hydrogen or alkyl; a, b, c and d are eachmole fractions of the respective polymer units and are each greater thanzero.
 36. A polymer that comprises repeat units of at least two distinctnorbornene repeat units.
 37. The polymer of claim 36 wherein the polymercomprises photoacid-labile groups.
 38. The polymer of claim 37 whereinthe one or both of the distinct norbornene units comprises aphotoacid-labile moiety, or the polymer comprises a photoacid-labilerepeat unit separate from a norbornene unit.
 39. The polymer of claim 38wherein the polymer comprises an acrylate unit having a photoacid-labilemoiety.
 40. The photoresist of any one of claims 36 through 39 whereinthe polymer is a tetrapolymer or a pentapolymer.
 41. A monomer that is a8-alkyl-tricyclodecanyl acrylate or 8-alkyl-tricyclodecanylmethacrylate.